401K'and IRAs make it hard to own physical gold and silver within those plans. It is possible to own gold vaulted in the hands of a third party or paper gold ETF's but the latter have always had a question mark if they really have the bullion to back up the claims on their fund. Some bullion dealers will tell you there is a way to hold gold or silver yourself in an IRA based on questoniable interpretations of the Internal Revenue Code, but that is a chance many will not take. All of our gold and silver is outside our retirement plans. There is a way that is compliant with IRS regs to set up residential real estate inside an IRA, and we maintain an account with a financial institution that specializes in doing so.
Central banks worldwide, with the notable exception of the Fed, have been big buyers of gold over the last few years, often buying it by the ton. I suspect they have more expertise in looking into the economic future than anyone on these boards. I read, for example where the Polish zloty had gained against the dollar and was not surprised given that the Polish central bank has been a big buyer of gold. A depression may not be what they are seeing, but some other economic dislocation. With the extreme debt levels of many countries, including our own, there are lots of opportunities for things to go south.
The 1929 depression was triggered by the failure of a bank in Austria. Around the world, there are way too many zombe banks out there today. I could name a few of them for you starting with Deutsche Bank. An instrument that is widespread today that I do not think even existed in 1929 that has been called "a weapon of mass financial destruction" is the credit default swap, which is a huge market and Deutsche Bank is by far the biggest player in it worldwide. At a point a few years ago when Deutsche Bank was particularly vulnerable, the question was asked if the German government would bail them out if they crashed. The answer was that NO, it would take more than the annual GDP of Germany to bail out Deutsche Bank, and it was beyond even the EU as a whole doing so.
Faced with a 1929 scenario today, I personally think most governments would try to stop it by running the printing presses wide open, which would set up some other economic challenges.